This invention relates generally to article abrading and more particularly to a multi-station shot blasting machine.
During the production of various metal articles, such as engine blocks, it is necessary to clean the article so as to remove scale, encrusted sand, rough metal burrs, flash and other remnants from the formation process.
Previous shot blasting machines have exhibited various limitations. One limitation arises because the articles themselves often have cavities, depressions, openings, corners and other surface irregularities. With articles of this type, the shot particles tend to collect within the various internal cavities and surface irregularities thus requiring that an additional production step, to remove the particles, be provided.
Another limitation of prior shot blasting machines is that they do not readily permit exposure and cleaning of all article surfaces, including those of the internal cavities. Typically, these machines employ holders which grip or clamp directly onto the surfaces of the article which are to be cleaned. These clamping-type holders prevent the surfaces of the article immediately thereunder from being cleaned. Another limitation associated with the clamping-type holders is that being within the harsh environment of the shot blaststream, these holders are subject to frequent mechanical malfunctioning. Also, to ensure that all sides of the article are abraded, the abrasive material must be applied from numerous blast wheels located around the article. Another limitation with prior machines is that often, the articles are not sufficiently cleaned by a single cleaning cycle.
With these and other limitations in mind, the present invention seeks to provide an apparatus which cleans all the surfaces of the article, including those associated with surface irregularities and internal cavities.
In furthering this object, the invention seeks to ensure that the article is fully cleaned after one full cycle through the abrading apparatus while reducing the number of blast wheels used to discharge the shot.
Another object of the present invention is to eliminate the need for a separate production step to remove any shot which has collected in the surface irregularities and internal cavities of the article.
In achieving the above objects, the invention provides for a shot blast machine having a multiple number of blast wheel stations or locations. The stations are adjacently positioned relative to one another to allow for one of the articles to be primarily shot blasted while the adjacent article, having already been primarily shot blasted, is incidently or redundantly cleaned by the shot being projected against the primary article.
The articles are successively advanced through the blast stations by an endless conveyor having fixtures for individually carrying the articles. The articles are held by gravity in inclined holders which support the articles during blast cleaning such that no clamp-type gripping of the articles is required. The holders are mounted to the fixtures so that the articles may be manipulated as they are transferred through the blast stations. The combination of the non-clamping holder and manipulation of the article allows for all the surfaces of the articles to be exposed to the abrading material and allows for a decreased number of blast wheels. The manipulation of the article also causes any abrading material which has accumulated within the surface irregularities of the article to be removed or dumped therefrom.
The result of the above invention is a simplified abrading apparatus that ensures efficient and complete cleaning of all of the surfaces of the article, while eliminating a production step for removing deposits of abrading material from the cleaned article.
Additional benefits and advantages of the present invention will become apparent to those skilled in the art to which this invention relates from the subsequent description of the preferred embodiment and the appended claims, taken in conjunction with the accompanying drawings.